Folding apparatus



June 18, 1963 E. F. KAMBERG FOLDING APPARATUS 4 Sheets-Sheet 1 Filed Jan. 31, 1961 INV EN TOR. {0?/4// A /%///fie/ June 1963 E. F. KAMBERG 3,094;32l

FOLDING APPARATUS Filed Jan. 31, 196

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June 18, 1963 E. F. KAMBERG 3,094,321

- FOLDING APPARATUS Filed Jan. 51, 1961 4 Sheets-Sheet s INV EN TOR.

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' FOLDING APPARATUS Filed Jan. 31, 1961 4 Sheets-Sheet 4 INV EN TOR.

United States Patent 3,094,321 FOLDING APPARATUS Eduard F. Kamberg, Des Plaines, Ill., assignor to Chicago Dryer Company, Chicago, Ill., a corporation of Illinois Filed Jan. 31, 1961, Ser. No. 86,118 11 Claims. (Cl. 270-68) This invention relates to apparatus for folding flat work such as sheets, tablecloths and the like, and more particularly pertains to apparatus which is adapted to automatically quarter-fold flat work and deliver the same in proper condition for cross folding.

The machines known in the art which are employed for folding flat work are usually subject to one or both of the following disadvantages. Such machines are usually of great length and occupy large floor areas. In addition, certain folding machines possess high-cost automatic timing and measuring devices which are generally considered to be the greatest cause of maintenance problems in machines of this type.

It is an object of this invention, therefore, to provide an automatic folding apparatus composed of durable conventional parts having long life which retain operational difliculties at a minimum.

It is a further object of this invention to provide an automatic folding apparatus in which edge portions of the article being folded effect physical contact with actuating apparatus elements, thereby dispensing with the need for automatic measuring or timing devices. It is another object of this invention to provide an automatic folding apparatus employing a novel folding meansconveyor arrangement which performs a plurality of folding operations while occupying a minimum amount of floor area.

It is a still further object of this invention to provide a flexible folding apparatus which is capable of receiving finished flat work from the highest production ironers and either quarter-folding, half-folding or by-passing the same.

The above and other objects of this invention will become apparent from the following detailed description when read in the light of the accompanying drawing and appended claims.

In one embodiment of this invention a folding apparatus is provided comprising a plurality of substantially horizontal conveyors at least partially superimposed over each other in spaced relationship. Each of said conveyors is formed from a plurality of continuous rotating tapes or belts. Articles to be folded, such as sheets or the like emerging upon the discharge belt of an ironer, engage the uppermost conveyor tapes and move in a direction away from the ironer or apparatus feed side.

The article leading edge engages a movable switch arm which actuates a first switch means after proceeding up a plurality of retractable inclined fingers disposed in. transverse alignment and inclined in the direction of tape movement. Upon switch actuation, clamping means engage the article leading edge and retain the same above the plane of the conveyor tapes as the inclined fingers simultaneously are retracted below the plane of the tapes by suitable motive means. The sheet continues to move beneath the clamping means, doubling upon itself, until a second switch actuator spaced in advance of said first switch and interposed between two of said tapes loses contact with the terminal end portion of the conveyed article. The clamping means motive means is then actuated to release its engagement with the sheet leading edge allowing the same to neatly drop upon the sheet terminal edge.

The leading 'bight portion of the half-folded article drops from the terminal end of the uppermost conveyor and engages the tapes of an adjacent underlying second conveyor proceeding in a direction opposite to the direction of firstconveyor movement. The half-folded article engages 3,094,321 Patented June 18, 1963 folding apparatus similar to that employed with the first conveyor and is quarter-folded while moving on the second conveyor. Following the second folding operation, the article free ends are disposed lowermost. The quarter-folded article leading portion drops from the second conveyor terminal end onto the tapes of an underlying th1rd conveyor moving in the direction of first-conveyor movement.

The twice-folded article may proceed from the apparatus on the lowermost conveyor onto a folding platform located on the discharge side of the apparatus. In the discharged condition the free ends of the twice-folded article are desirably in an uppermost position for cross folding, as will hereinafter be discussed in greater detail.

For a more complete understanding of this invention, reference will now be made to the drawings wherein:

FIGURE 1 is a side elevational View, partly broken away and partly schematic in nature, of one embodiment of folding apparatus of this invention;

FIG. 2 is an enlarged fragmentary top plan view of the apparatus of FIG. 1, illustrating a housing in place partly broken away;

FIGS. 3 through 6 are fragmentary side elevational views partly schematic in nature depicting the sequence of steps carried out in the course of folding a sheet by means of the folding apparatus illustrated; and

FIG. 7 is a perspective view of a folded sheet in its normal position upon emergence from the folding apparatus illustrated.

Referring now more particularly to FIG. 1, a folding apparatus 10 is illustrated having opposed side plate members 12 and 14. The plates are maintained in spaced relation by means of transverse brace members 16, an enlarged fragment of one of said brace members being seen in FIG. 2. Secured to the opposed apparatus side wall members 12 and 14 are adjustable bearing members 18 in which are journaled parallel roller members 20 and 20a over which three sets of continuous conveyor tapes move. The tapes 22 are more clearly seen in the plan view of FIG. 2. The uppermost tapes define a conveyor 24; the lowermost tapes define a conveyor 26, and the intermediate tapes disposed therebetween define a conveyor 28.

In the normal course of operation of the apparatus 10 of FIGS. 1 and 2, a sheet (or other article to be folded) is engaged by the tapes of conveyor 24 with the sheet selvage edges defining the length thereof disposed transversely to the conveyor direction of movement. Conveyor fragment 30 illustrated in FIG. 1 may comprise the discharge conveyor of an automatic ironing device disposed adiacent the feed side of the folding apparatus 10.

Motor 36 drives rollers 20a which impart movement to the various tape members 22 making up the three con gaging sprocketchain 45 schematically illustrated in FIG.

1. The latter sprocket chain in turn rotatably drives sprocket wheels 46, 48 and 50 which are mounted on terminal portions of the rollers 20a as indicated in FIG. 1.

The diameters of sprockets 46, 48 and 50 are of diminishing size and, accordingly, each of the two lower conveyors 28 and 26 moves at a more rapid rate of speed than the conveyor disposed immediately thereabove. It is also obvious from FIG. 1 that because of the manner of sprocket chain engagement with sprocket Wheels 46, 48 and 50 and resulting direction of rotation, the upper conveying surfaces of conveyors 24 and 26 move toward apparatus discharge platform 34. The upper conveying surface of intermediate conveyor 28 moves in the opposite direction, i.e., toward the feed side of the illustrated apparatus 10.

A sheet or other article of flat work passing through apparatus 10 is folded twice in the'course of being conveyed by the two conveyors 24 and 28. FIGS. 3 through 6 illustrate the manner in which the conveyed article is folded. It will be appreciated from FIG. 1 that FIGS. 3 through 6 illustrate the initial half-folding operation effected on uppermost conveyor 24. However, the same sequence of operations also takes place on underlying conveyor 28. In view of the different direction, of conveyor movement, the folding elements employed, in conjunction with conveyor 28 are inclined in a reverse manner from the elements employed in FIGS. 3 through 6, as is also seen in FIG. 1.

In the course of moving on conveyor 24, leading edge L of a sheet S or other foldable article deflects arm 54 of electric switch 56 from its normal vertical position in the manner illustrated in FIG. 3. This deflection of arm 54 closes electric switch 56' but, does not result in the actuation of any apparatus until: another switch in series therewith is also closed, as hereinafter described.

After passing beneath the terminalend of switch arm 54, leading edge L of sheet S proceeds up inclined,- transversely aligned finger-like members 60 which are secured to the pivot bar 62. Thealignment of fingers 60' may be more clearly seen from FIG. 2. After proceedingover fingers 60, leading edge L of sheet S engages and deflects arm 64 of electric switch 66 from its'normal vertical position in the manner illustrated in FIG. 3-, thereby closing said switch, which is connected in series with electric switch 56.

Electric switch 66. upon closurev thereofbyswitch arm. 64 completes an electrical circuit, energizing a coil in a conventional four-way solenoid valve. device: 70 illustrated in both FIGS. 1 and 6, which is in communication. with a compressed air supply by means of line 72. Energization of such coil moves a spring-biased valve within. the device 70, allowing compressed air to flow into the bottom portions of air cylinders 74 and 76 illustrated in. FIGS. 1 and 6. As a resultof such. flow, pistons (not illustrated) move upwardly in the two, cylinders. It will be noted from FIG. 2 that a housing 73 may. cover the air cylinders and other apparatus disposed exteriorly of wall 12. I h

Upward movement of piston rod 78 of air; cylinder 74, and attached clevis member 80, also moves upwardly link 82 connected to clevis 80 by pin 84, as indicated in FIG. 6. Link 82 in turn pivotally moves. bar 86 in a clockwise direction about its pint'les, one pintle 864, being shown in FIG. 2,. by means of in terconnecting arm 88 which is pivotally connectedto link 82 and fixedly connected to bar 86. Clockwise pivotal movement of bar 86 causes downward pivotal movement of clamping rod 90 which is connected. to pivoting bar 86. by means of a plurality of interconnecting supporting fingers 92; the spacingof the support fingers 92 which connect clamping rod 90 and pivoting bar 86 is seen in FIG. 2.

As a result, therefore, of movement of switch arm 64, electric switch 66 completes a circuitenergizing a coil of valve 70. The coil in the energized state moves a spring-biased valve member in solenoid valve 70 whichv alters air passage into cylinders 74 and 76. The resulting air flow in turn actuates the piston in cylinder 74 so that clamping rod 90 instantaneously pivots downwardly clamping a forward portion of the sheet S against the underlying surface of a fixed plate 57. Plate 57 is maintained in a fixed position by means of support 96 mounted in opposed side plates 12 and 14 of the apparatus. Plate 57 is, therefore, seen to function as an anvil-like member against which clamping rod 90 may strike for the purpose of fixedly retaining the forward edge portion of the moving sheet S. Plate 57 is slot-tedat 59 to permit passage of an pivotal movement of actuator arm 64.

Simultaneously with the introduction of air into the bottom portion of air cylinder 74, air is also admitted by means of solenoid valve 70-into the bottom portion of air cylinder 76, whereby thepiston (not illustrated) in cylinder 76 and attached piston rod 98 and clevis 100 move upwardly (see FIG. 6). The compressed air passes from solenoid valve 70 to the bottom of cylinder 76 by means of line 102. Upward movement of clevis 100 also moves upwardly link 104 pivotally connected to clevis 100 by means of pin 106. Upward movement of link 104 pivotally moves bar 62 in a clockwise direction by means of arm 63, which is locked to bar 62 on which inclined fingers 60 are mounted. The fingers 60 are thereby retracted from their elevated inclined position of FIG. 3 into the lowered horizontal position of FIG. 4 beneath the plane of the upper portions of the tapes of conveyor 24. Retraction of fingers 60 enables the portion of the sheet S contiguous with the forward portion clamped between rod 90 and anvil plate 51150 be carried by the conveying tapes of conveyor 24 beneath the clamping mechanism in the manner illustrated in FIG. 4.

To effect a half-fold whereby the sheet is folded substantially in two, clamping rod 90 must be withdrawn from engagement with the forward portion of sheet S. counterclockwise pivotal movement of bar 86 is effected when the terminal edge. T of sheet S loses engagement with actuator arm 54 of switch 56, allowing arm 54,to depend into its normal vertical position.

The actuator arm 54 is normally disposed in the interval between two tapes22. Return of arm 54-to the vertical position in the manner illustrated in FIG. 5. opens the switch 66 to break the circuit energizing the coil of solenoid device 70 allowing the spring return to move the valve. In the new position the movable valve in solenoid, device 70 allows air to enter the upper end portions-of air cylinders 74;and 76 by means of air lines 112. The pistons within the cylinders and attached rodsare thus forcedto move in a downward direction. Air within the cylinders in the course of piston reversal is also forced from the cylinder chambers and returned to the solenoid valve from which it exits through escape ports. Escape, port 114 of solenoid 70 (see FIG. 6) has an air flow control device 116; (which may comprise a needle valve) disposed therein whereby the air escaping from cylinder 76 exits from said cylinder at a controlled rate causing fingers 60 to slowly return to their initial inclined position of FIG. 3 and FIG. 6, so as not toengage-and wrinkle the rear portions of the folded sheet S. The initial upward movement, however, of hold-down; rod member 90 substantially instantaneously releases the leading edge portion of sheet S.

The relative disposition assumed between leading edge;

to hold-down rod 90, leading edge L of sheet S will drop,

and extend beyond terminal edge T when released. Conversely, if actuator arm 54 is disposed too far from 1101(11 downrod 90, the leading edge L of sheet S will drop on a sheet portion inwardly disposed of the. sheet terminal edge T.

The disposition of the leading edge L of sheet S relative to terminal edge T of sheet S is also a function of the speed of the tapes of the conveyor 24. Accordingly, the switches 56 and 66 are adjustable to compensate forvarying conveyor speeds, thereby assuring release of the leading edge L of sheet S so that the same will drop over terminal edge T after upward movement of rod 90. Any conventional means for adjustably positioning switches 56 and 66 may be employed, such as turn buckles 120' which threadedly engage connector portions 122 secured to eachof the two switches at one end portion. The turn buckles threadedly engage threaded support members 124 appropriately mounted on a portion of the apparatus at opposed end portions.

The folding operations above described reseult in halffolding of sheet S on conveyor 24. Referring once again to FIG. 1, it will be noted that upon dropping from the right-hand end portion of conveyor 24, the leading-bightte e211 portion of folded sheet S will drop onto underlying coniveyor 28 which is movingin a direction opposite to :the direction of movement conveyorzfi. Each of the two lower conveyorsv extends slightly beyond-the discharging terminal end of the immediately overlying .conveyor to assure engagement. of .the .article. dropping from. above.

Becauseof the relative sizes of the .sproekets46 and 48 secured to rollers 204, drivingoonveyors 24 and ,2 8,fthe tapes of conveyor'28 move ata rnorerapid speed. Also, the terminal. end, of. conveyorlst isspacedajshort distance from the receiving end of conveyor 28. Accordingly, wrinkling ofthedependingyfoldedsheet moving from conveyor 24 onto conveyor 28 isobv-iated inrth'e course of transfer. The sheet portion initially engaging conveyor 28 because of itsincreased .speedrtendsto pull the sheetportion .yet disposed in conveyor 2.4 after it, thereby creatinga tautness which insures wrinkle removal if any be present in the sheet.

Th ha o d sheetin thecourse o i g o -conveyor 28 engages inclined fingers 604, ho ldrdown .bar;90a

vand the other folding, elements .disposed above conveyor 28 and beneath con'veyor-,24, as seen in .FIG. 1. ,It will be noted from FIG. .1 that thetelements elfecting a quarter-foldon sheet S in the course of movingonconveyor 28 are exactly the same as the elementslpreviously described in .the above discussion of FIGS. -3 through 6, althoughinclined in an opposite direction. It will also be noted from ,FIG. 1 that the elementseifecting the second fold insheet S bearthe same identifyingnnmerals as corresponding elements which eflectthe initial fold of the sheet in addition to a su'fiix a.

The quarter-folding elements engage the leading b ight portion'of the half-folded sheet and dropthesame slightly beyond the terminal free selvage edges T and L of the now quarter-folded sheet; a distance of about one inch has been found satisfactory. After passing beyond the folding station employed in conjunction with conveyor 28, the quarter-folded sheet will have the crossrsectional configuration of the sheet illustrated on conveyor 28 in FIG. 1.

It is desired .thatfthe leading edge L .of sheet S be disposed in substantially superposed relationship with terminal edge Tof sheet S in the course of effecting .a halffold. It is desired that when the quarter-fold is effected, folded bight portion B of the halffolded sheet be dropped beyond selvage edges T and-L of sheet S for'reasons which will become apparent.

The qnarter folded sheet S upon reaching the terminal end portion of conveyor 28 drops to the underlying third conveyor 26 which moves oppositely to 'conveyor 28 for purposes of deliveringthe folded sheet to a discharge platform 34. Because of the relative sizes of sprockets 48 and 50, roller a of conveyor 26 rotates more rapidly than roller 20a of-conv'eyor 28 and, accordingly, the quarter-folded sheet will be again pulled by the conveyor 26 from conveyor 28, thereby tending to eliminate any wrinkles which may have formed in the folded sheet.

The qua-rer-folded sheet moves onto discharge platform 34 at which location selvage edges L and T are disposed uppermost, set'in from underlying bight edge "B of sheet S. A perspective view of the sheet as normally disposed on platform 34 is seen in FIG. 7. The quarterfolded sheets of FIG. 7 is then cross-folded by folding the left-hand third portion along fold line F until'the same is superposed abovethe central third section of the sheet. The right-hand thirdsection of the sheet is folded over the other twosuperposed third portions of the sheet.

Because of the final disposition of the sheet selvage edges (comprising terminal edges L and T) they will not be visible after the final cross folding operation. The final folded sheet, therefore, possesses a pleasing attractive appearance in which no free selvage edges are visible.

iltis seen, therefore, that the quarter-folded sheet should reach the discharge platform ,34 in the condition illustrated with the free selvage edges thereof disposed uppermost, set .in from the bight edge 3 of the sheet. If the sheet were discharged from the machine :10 with the selvage .edge's disposed lowermost, a cross folding operation would provide an unsightly folded sheet :in which unattractive selvage edges are exposed. In 'view of the normally long lengths of the flat Work folded, -ajs'hee1t -S discharged upon platform 34 with the sch/age =edge's %disposed lowermost cannot normally be inverted and crossfolded (assuming the cross folding is done manually) without causing wrinkles to appear in the sheet.

7 A folding apparatus has, therefore, been provided which is composedof a minimum'nurnber of conventional parts which assure long trouble-free operation .and mini mum maintenance costs. FIhe means for effecting the quarter and half-fold are actuated as a result of physical oontact of sheet portions with well-known switch actuatormembers avoiding completely the need for automatic timing and measuring devices. Although two folding voperations are performed on the fiat work beingprocessed', the length of machine 10 is no longer than that length which would be necesary if only one of the three conveyors were employed. The apparatus 10, therefore, :by meansof its novel conveyor arrangement makes optimum use of the machine volume. The apparatus above described and illustrated in the drawing "may be manufactured at a fraction of the cost normally expendedin manufacturing machines 20f similar type for effecting the :same ldin pe at ons- -Cer tain modifications may be made in the previously described apparatus which will still remain within the ambit of the invention disclosed. ;It is obvious, for instance, that a variety of motive means may be employed for efiecting desired pivotal movement of the retractable fingers 60 and 60a and the hold-down rod members 90 mi wa- FIhe-speeds of the conveyors 24, ;28 and 2.6 are of some importance. ['he tapes of conveyor 24 should be able to move faster thanthefastest discharge conveyor of ironers normally in use v( approximately feet per minute). Also, eaohofthe twolower conveyors shouldfhave a greater speed than the conveyor irrunediatejly disposed thereabove. 'It has been found that'the maximum speed of the uppermost conveyor is in the neighborhood of 95 feet per minute, and to feet per minute has been found tobe-a satisfactory range. Any speed in excess of the maximum results in flying off of the half-folded sheet from the terminal end portion of conveyor 24 so that the same may not be properly engaged by the underlying conveyor 28.

The speed of conveyor 28 should not exceed approximately 115 feet per minute and should be inclined at an angle of no greater than 15 to the horizontal. Speeds therange of to feet per minute have been found satisfactory. The inclination of conveyor 28gprovides space for the second set of folding-elements. Conveyor 28 is able to travel at a speed greater than conveyor 24 without article flyoif because of the heavier double-folded sheet leaving the terminal end of conveyor 28. The lowermost conveyor 26 should preferably have a speedof no greater than 165 feetrper minute and a suitable range has been found to .be about to feet a minute. If the angle of the intermediate conveyor is inclined towardthe dischargeend of the first conveyor at an angle greater than 15 relativeto the horizontal, there is a tendency for the sheet to tiy oif the endof this conveyor. The interval between the discharge terminal end of an overlying vconveyor and the receivingendof an underlying conveyor is preferably as small as possible to allow a minimum length of conveyed article todrop unsupported onto the underlying conveyor and thereby obviate wrinkling in the course of article transfer. 7

By deactivating one set of folding elements, as by means of a selector switch, fiat Work passing through the apparatus 10 may be half-folded only. if desired, as whensma'll pieces such as pillow cases pass through the apparatus, both sets of folding elements may be deactivated (with the sets of inclined fingers dipos'edbelowthe' 7 planes of the conveyors, which may be accomplished by the closure of selector switch contacts completing a circuit around or in parallel with either the series combination of switches 56 and 66 or the switch 66 alone), and all work is then passed through the machine with no folding operation taking place.

[t is intended that this invention be limited only by the scope of the appended claims.

I claim:

1. In a folding apparatus, the combination comprising first conveyor means for conveying articles to be folded, retractable means for lifting the leading edge of a conveyed article, said conveyor means feeding the leading edges of successive articles onto said retractable means, fixed anvil means disposed in the path of the leading article edge moving over said lifting means, movable clamp means movable against said anvil means, article detector means so located as to be engageable by the leading edge of a conveyed article moving over said anvil means, means responsive to said detector means for urging said clamp means against said anvil means and for lowering said retractable lifting means after said article detector means has been engaged by the leading edge of a conveyed article, second article detector means located in advance of said anvil means in the path of said conveyed article sensitive to disengagement with the terminal edge of said conveyed article, means for removing said clamp means from engagement with said anvil means responsive to said disengagement whereby said clamp means is removed from said anvil upon disengagement of said article terminal edge with said second detector means, means for raising said retractable means, the raising means also being sensitive to disengagement of the terminal edge of said conveyed article with said second detector means; and means operatively connected with said latter raising means for regulating the speed at which said retractable means are raised.

2. The combination of claim 1 in which the interval between said second article detector means and said clamp means is such that the leading edge of said conveyed article when released by said clamp means is substantially superposed on the terminal edge of said conveyed article.

3. In a folding apparatus the combination comprising first substantially horizontal conveyor means for conveying foldable articles, second substantially horizontal conveyor means; said first conveyor means being in substantial part superimposed over said second conveyor means; third substantially horizontal conveyor means, said first and second conveyor means being in substantial part superimposed over said third conveyor means; successive conveyors in said apparatus running in opposite directions; each of the lower conveyors running at a greater speed than the conveyor above, the initial portion of each of the lower conveyors being so located relative to the immediately overlying conveyor that the leading end of a conveyed foldable article may drop from the overlying conveyor onto the underlying conveyor whereby said conveyors may successively convey a foldable article moving thereover, and folding means for folding an engaged foldable article while carried by a conveyor associated with each of said upper two conveyors in such manner that said foldable articles are carried by each of said upper two conveyors into engagement therewith.

4. In a folding apparatus the combination comprising a first substantially horizontal conveyor means for conveying foldable articles, means associated with said first conveyor means for engaging, lifting and dropping the leading end portion of the foldable articles conveyed on said first conveyor means on substantially the terminal end portion of said conveyed articles; second substantially horizontal conveyor means disposed in substantial part beneath said first conveyor means and so located relative to said first conveyor means whereby the leading end of a conveyed foldable article may drop from the first conveyor means onto the second conveyor means; means associated with said second conveyor means for engaging,

lifting and dropping the leading edge of the foldable article discharged from the first conveyor means on substantially the terminal end portion of the discharged foldable article; third substantially horizontal conveyor means disposed in substantial part beneath said first and second conveyor means and so located relative to said second conveyor means that the leading end of a conveyed foldable article may drop from the discharge end of said second conveyor means onto said third conveyor means; said second conveyor means running in a direction opposite to that of said first and third conveyor means.

5. In .a folding apparatus, the combination comprising three substantially horizontal conveyors for successively conveying a foldable article; said conveyors being in substantial part superimposed over each other, successive conveyors moving in opposite directions; the discharge end of each of the two upper conveyors terminating adjacent the receiving end of the immediately underlying conveyor whereby the leading end portion of a conveyed foldable article may drop from the discharge end of a conveyor and be engaged by the adjacent, underlying conveyor receiving end, and folding means for folding an engaged foldable article while carried by a conveyor :associated with each of said upper two conveyors in such manner that said foldable articles are carried by each of said upper two conveyors into engagement therewith.

6. In a folding apparatus, the combination comprising three substantially horizontal conveyors for successively conveying .a foldable article; said conveyors being in substantial part superimposed over each other, successive conveyors moving in opposite directions, the discharge end of each of the two upper conveyors terminating adjacent the receiving end of the immediately underlying conveyor whereby the leading end portion of a conveyed foldable article may drop from the discharge end of a conveyor and be engaged by the adjacent, underlying conveyor receiving end; the speeds of each of the two lower conveyors being greater than that of the immediately overlying conveyor whereby a foldable article in the course of moving from one conveyor to an underlying conveyor has the leading portion thereof traveling at a greater rate of speed than the terminal portion thereof, and folding means for folding an engaged foldable article while carried by a conveyor associated with each of said upper two conveyors in such manner that said foldable articles are carried by each of said upper two conveyors into engagement therewith.

7. In a folding apparatus, first substantially horizontal conveyor means for conveying a foldable article, first folding means associated with said first conveyor means for engaging the leading edge of a foldable article and positioning the same on substantially the terminal edge of such foldable article while said article is being conveyed, said first conveyor means moving said foldable article into engagement with said first folding means, the bight of the once-folded article being the leading portion of the article following said folding operation; second substantially horizontal conveyor means so disposed beneath said first conveyor means that the bight of the once-folded article may drop from the terminal end of said first conveyor means and engage the same and move in a direction opposite to the direction of movement of said first conveyor means, second folding means associated with said second conveyor means for engaging the bight of the once-folded article carried by said second conveyor means and positioning the same on substan' tially the terminal edges of said foldable article whereby the free edges of said foldable article are lowermost and trail the bight of the twice-folded article, said second conveyor means moving the bight of said once-folded article into engagement with said second folding means, and third substantially horizontal conveyor means movable in the direction of movement of said first conveyor means so disposed beneath said second conveyor means that the bight of the twice-folded article may drop from said second conveyor means, engage the third conveyor means and move in the direction of movement of said first conveyor means; said first and second conveyor means being in substantial part superimposed over said third conveyor means; the speeds of the successive conveyor means becoming progressively greater whereby the folded articles are pulled from the overlying conveyor means and inverted in the course of moving from conveyor means to conveyor mean-s.

8. In a folding apparatus, the combination comprising first substantially horizontal conveyor means for conveying articles to be folded, first folding means associated with said first conveyor means for engaging the leading edge of a moving article to be folded carried by said first conveyor means and dropping the same on substantially the terminal edge of such article whereby the same is folded substantially in half, second substantially horizontal conveyor means moving in a direction opposite to the direction of movement of said first conveyor means extending in substantial part beneath said first conveyor means and slightly beyond the terminal end of said first conveyor means whereby the once-folded article may drop from said first conveyor means to said second conveyor means, second folding means associated with said second conveyor means for engaging the bight portion of the once-folded article and dropping said bight portion on an article portion spaced from the terminal free edges of said article whereby said article is folded substantially into quarters, third substantially horizontal conveyor means disposed in substantial part beneath said second conveyor means and moving in the direction of movement of said first conveyor means and extending beyond the terminal end of said second conveyor means whereby the twice-folded article may drop from said second conveyor means onto said third conveyor means; said twice-folded article having the sheet terminal free edges disposed uppermost and supported upon an underlying ar-ticle portion upon discharge from said apparatus.

9. The folding machine of claim 8 in which said first conveyor means has a speed of between about 85 and 95 feet per minute, said second conveyor means has a speed of between about 105 and 115 feet per minute and said third conveyor means has a speed of between about 155 and 165 feet per minute.

10. In a folding apparatus, first substantially horizontal means for conveying an article to be folded, first folding means associated with the first conveying means for engaging the leading edge of an article to be folded and releasing the same when the terminal edge of said article is in predetermined relationship relative to said leading edge, the first conveying means being adapted to move the leading edge of a conveyed article to be folded into engagement with said first folding means, second article conveying means disposed beneath the first conveying means in substantial part and extending beyond the terminal discharge end thereof, said second conveying means being adapted to move in a direction opposite to the direction of movement of said first conveying means, said second article conveying means being inclined at an angle of less than to the horizontal and inclined toward the first conveying means terminal end, the oncefolded conveyed article being moved from said first conveying means onto said second conveying means with the bight of the once-folded article comprising the leading portion, second folding means associated with said second conveying means for engaging the bight portion of the once-folded article and releasing the same when the terminal edges of said article are in such relationship relative to said bight portion that said bight portion will assume a substantially superposed relation with the article free edges following release thereof, said second conveying means being adapted to move the bight of a conveyed article into engagement with said second folding means, third substantially horizontal conveying means moving in the direction of said first conveying means disposed in substantial part beneath said first and second conveying means and extending beyond the terminal discharge end of said second conveying means, the speeds of the successive conveying means becoming increasingly greater whereby articles are pulled from the conveying means above and inverted in the course of moving to a lower conveying means.

11. In a folding apparatus, the combination comprising three substantially horizontal conveyors for successively conveying a foldable article; said conveyors being in substantial par-t superimposed over each other, successive conveyors moving in opposite directions; the discharge end of each of the two upper conveyors terminating adjacent the receiving end of the immediately underlying conveyor whereby the leading end portion of a conveyed foldable article may drop from the discharge end of a conveyor and be engaged by the adjacent, underlying conveyor receiving end, and folding means for folding an engaged foldable article while carried by a conveyor associated with each of said upper two conveyors in such manner that said foldable articles are carried by each of said upper two conveyors into engagement therewith, said folding means comprising retractable means for lifting the leading edges of a conveyed article, fixed anvil means disposed in the path of the leading article edge moving over said lifting means, movable clamp means movable against said anvil means, article detector means so located as to be engageable by the leading edge of a conveyed article moving over said anvil means, means responsive to said detector means for urging said clamp means against said anvil means and for lowering said retractable lifting means after said article detector means has been engaged by the leading edge of a conveyed article, second article detector means located in advance of said anvil means in the path of said conveyed article sensitive to disengagement with the terminal edge of said conveyed article, means for removing said clamp means from engagement with said anvil means responsive to said disengagement whereby said clamp means is removed from said anvil upon disengagement of said article terminal edge with said second detector means, means for raising said retractable means, the raising means also being sensitive to disengagement of the terminal edge of said conveyed article with said second detector means; and means operatively connected with said latter raising means for regulating the speed at which said retractable means are raised.

References Cited in the file of this patent UNITED STATES PATENTS 2,308,155 Clegg Jan. 12, 1943 2,740,627 Woodward et a1 Apr. 3, 1956 2,811,350 Cran et a1. Oct. 29, 1957 2,949,294 Cran Aug. 16,1960

FOREIGN PATENTS 693,351 Britain July 1, 1953 512,524 Canada May 3, 1955 

3. IN A FOLDING APPARATUS THE COMBINATION COMPRISING FIRST SUBSTANTIALLY HORIZONTAL CONVEYOR MEANS FOR CONVEYING FOLDABLE ARTICLES, SECOND SUBSTANTIALLY HORIZONTAL CONVEYOR MEANS; SAID FIRST CONVEYOR MEANS BEING IN SUBSTANTIAL PART SUPERIMPOSED OVER SAID SECOND CONVEYOR MEANS; THIRD SUBSTANTIALLY HORIZONTAL CONVEYOR MEANS, SAID FIRST AND SECOND CONVEYOR MEANS BEING IN SUBSTANTIAL PART SUPERIMPOSED OVER SAID THIRD CONVEYOR MEANS; SUCCESSIVE CONVEYORS IN SAID APPARATUS RUNNING IN OPPOSITE DIRECTIONS; EACH OF THE LOWER CONVEYORS RUNNING AT A GREATER SPEED THAN THE CONVEYORS ABOVE, THE INITIAL PORTION OF EACH OF THE LOWER CONVEYORS BEING SO LOCATED RELATIVE TO THE IMMEDIATELY OVERLYING CONVEYOR THAT THE LEADING END OF A CONVEYED FOLDABLE ARTICLE MAY DROP FROM THE OVERLYING CONVEYOR ONTO THE UNDERLYING CONVEYOR WHEREBY SAID CONVEYORS MAY SUCCESSIVELY CONVEY A FOLDABLE ARTICLE MOVING THEREOVER, AND FOLDING MEANS FOR HOLDING AN ENGAGED FOLDABLE ARTICLE WHILE CARRIED BY A CONVEYOR ASSOCIATED WITH EACH OF SAID UPPER TWO CONVEYORS IN SUCH MANNER THAT SAID FOLDABLE ARTICLES ARE CARRIED BY EACH OF SAID UPPER TWO CONVEYORS INTO ENGAGEMENT THEREWITH. 